Extrahepatic Biliary Tract Obstruction

Abstract

The earliest known disease of the extrahepatic biliary tract (EHBT) is gallstones, which date back to the twenty-first Egyptian Dynasty and were discovered in the mummy of the Priestess of Amen. The diseases that lead to a need for surgery of the EHBT in dogs are primarily acquired conditions and include EHBT obstruction, gallbladder mucocele, traumatic injury, and cholecystitis. The primary diagnostic problem in evaluating dogs with icterus is differentiating between an extrahepatic obstructive lesion and a primary hepatic parenchymal disease process. Ultrasound is a sensitive and specific indicator of the cause of EHBT obstruction. Causes of EHBT obstruction in small animals include cholelithiasis, neoplasia, pancreatitis, inspissated bile, gallbladder mucoceles, parasites, duodenal foreign body, and diaphragmatic hernia. The diseases that lead to a need for surgery of the extrahepatic biliary system in dogs and cats are primarily acquired conditions and include EHBT obstruction, gallbladder mucoceles, traumatic injury, and cholecystitis.